/*
https://www.nowcoder.com/practice/eb94f6a5b2ba49c6ac72d40b5ce95f50?tpId=37&&tqId=21233&rp=1&ru=/ta/huawei&qru=/ta/huawei/question-ranking
*/

#include <stdio.h>
#include <string.h>
int main() {
    //输入
    char arr[501] = {0};
    scanf("%s", arr);
    int length = strlen(arr);
    //创建哈希表
    int hash[130] = {0};
    for (int i = 0; i < length; i++) {
        if (arr[i] >= 0 && arr[i] <= 127) {
            ++hash[arr[i]];
        }
    }
    //记录种类
    int count = 0;
    for (int i = 0; i < 130; i++) {
        if (hash[i]) count++;
    }
    printf("%d\n", count);
    return 0;
}